A neuropsychological profile of dementia was drafted for individuals with Alzheimer's Disease, Huntington's Disease and 'at risk' for Huntington's Disease. The evaluations extended into memory, learning and perceptual sectors, utilizing standard and experimental tasks, also establishing normative references for functional changes accompanying the aging processes. These behavioral data will be collated with biochemical and neuroradiometric measures, and independent indicators of deterioration and dementia will be developed.